In recent years magnetic resonance thermometry has been coupled with various means of heating or cooling tissue for therapy. Measuring the effect of the tissue heating or cooling allows the guiding of the therapy and also the ability to assess the effect of a therapeutic treatment on a subject.
In high-intensity focused ultrasound (HIFU) therapy, reliable real-time temperature monitoring using e.g. MRI is necessary to ensure a sufficient thermal necrosis to the target while avoiding excessive heating and damage of surrounding healthy tissues. To achieve sufficient temporal and spatial resolution, fast imaging is required preferably with a high spatial resolution while maintaining a sufficient SNR for reconstruction of reliable temperature measurements.
In Wlodarczyk et. al., “Three-Dimensional Monitoring of Small Temperature Changes for Therapeutic Hyperthermia Using MRI,” Journal of Magnetic Resonance Imaging, Vol. 8, pp. 165-174, the keyhole technique was used to accelerate magnetic resonance temperature using a pulsed diffusion gradient spin echo pulse sequence.